The FNAF 2 4/20 Custom Night challenge is actually pretty easy if you have a good strategy. Strategy:
1: Flash your flashlight down the hallway. If Foxy is there, flash it 5-7 times.
2: Pull up the camera; wind the music box.
3: Pull down the camera and put on the mask.
4: Repeat.
This should get you to victory! For a prize you get the 3rd star on the Main Menu. Please comment below if I should do more Custom Night tutorials.